I think your pushing the shoulder back to far , it sounds like a headspace problem . Mike if you have a factory round shoot it in your TC and adjust your sizing die to just size the neck of the case. my 2 cents

I have a 35 Rem Contender and have to be careful what factory loads are fed to it, Win loads get a lot of light primer hits and no bang. Rem factory loads have been very reliable so far with no misfires yet. Have not yet started to reload for it, but do have plenty of supplies waiting, and plan to not size down far enough to push the shoulders back. If that proves to still give erratic ignition, I may leave the bullets out far enough to make a tight fit against the breech face, use light to moderate loads, and fire form the cases to make sure they headspace correctly in that chamber. Of course, I do not have any other 35 Rem guns, so mixing up loads and putting them in the wrong chamber is not likely to happen.

Don't trash the brass. I would take it off your hands before you go that far.

More than likely what others have mentioned. There isn't a ton of shoulder and you can get misfires if you push the shoulder back too far. I have never had a misfire with my marlin or model 8 using CCI or Winchester primers. What type of primers are you using? My contender will not set off a Wolf LR primer reliably. Several other rifles have given me issues with them in the past as well.

One of the easiest way to get the shoulder pushed back out if you did push it in too far is to get some cast bullets and seat them where ithey engage the rifling. It should be snug to fully chamber. That will hold the case back against the breech face and blow the shoulder back forward.

Also are you getting a dent in the primer? If not the lugs on the Contender may not be fully engaging. My Super 14 .35 has to be snapped shut fairly hard or the lugs won't engage fully and then firing pin doesn't hit the primer. It clicks like a misfire, but there Is no dent.

MIGHT have thought that the hammer spring needed to be replaced (on the Contender). I was surprised that when it reaches that point where the spring crosses the line from acceptable to non-functional it seems to happen suddenly.

--
Sincerely,

Hobie